a) Field of the Invention
The instant invention relates to a support and housing for integrated circuit boards, and in particular to a support structure which serves to eliminate displacement and vibrations imposed on circuit boards adapted for use in high vibration environments.
b) Description of Related Art
Electronic control and regulating systems are being used increasingly in motor vehicles, the components of which are accommodated in housings to protect them from the stresses and vibrations occurring in operation. In installations where the printed circuit boards are subject to vibration, as in moving vehicles such as aircraft and automobiles, the circuit boards tend to vibrate or oscillate with maximum motion of vibration both at their centers and edges due to the resonant response of the board material. This excessive vibration or "oil canning" causes failure of components and solder connections. Moreover, during assembly, many board designs incorporate erasable/programmable read-only memory (EPROM) components which are inserted and retracted from the circuit board after being secured in the housing assembly. This too causes stress failure in the circuit board arrangement.
Many prior art attempts have been made to solve the vibration and stress concentration problem. U.S. Pat. Nos. 5,198,279 and 3,022,448 teach a frame member which is bolted to the board during assembly. However, this arrangement requires additional fasteners and increases assembly time. U.S. Pat. No. 3,324,974 discloses a cross-shaped damper formed of visco-elastic material which secured to one side of the circuit board. U.S. Pat. No. 3,631,297 discloses a rigid foam which is sandwiched between the circuit board and a metallic support plate. In the above designs, it is difficult to provide a circuit board assembly with adequate heat transfer for the relative small space or volume requirements encountered in vehicles designs.